1. Field of the Invention
This invention relates to a storage and dispensing container for compositions that are made of two or more components. The container stores at least two of the components in isolation from each other until a quantity of the composition is needed for use.
2. Description of the Related Art
Many useful compositions are made of two components that are not normally mixed together until immediately prior to the time that a quantity of the composition is needed for use. For example, the components of epoxy-based adhesives are stored separately from each other, because once the components come into contact with each other a chemical reaction is undertaken that eventually turns the mixed composition into a hardened mass. For that reason, epoxy-based adhesives are widely available in packages that include two compartments or two separate containers that keep the components of the adhesive initially isolated from each other.
Some packages for multiple-component compositions are relatively large and include a sufficient quantity of the components for multiple applications at different times. For example, epoxy adhesives are commonly available in bulk containers such as cans, jars and squeezable tubes. One component of the adhesive (often called xe2x80x9cPart Axe2x80x9d) is supplied in one bulk container, and the other component (often called xe2x80x9cPart Bxe2x80x9d) is supplied in another container that typically matches the first container in shape and construction. Such bulk containers are in widespread use because the costs of packaging the components are relatively low.
To prepare an adhesive from the components stored in bulk containers, a quantity of each component is measured, withdrawn from the container and transferred to a mixing location. The mixing location may be a mixing well, a mixing pad or a third container. Next, the user mixes the components and, using a spatula, brush or other suitable tool, transfers the mixed components to an application site.
However, the practice of supplying multiple-component compositions in two bulk containers is not entirely satisfactory. If, for example, the user does not withdraw the components from the bulk containers in the proper ratio, the characteristics of the resulting composition may be significantly impaired. Additionally, the portion of the components that remains in the container may be adversely affected over a period of time by exposure to the atmosphere once the container is opened. The user is also compelled to dispose of the mixing pad, well or other mixing container after a single use, or undertake an effort to clean the same in preparation for a subsequent use. Furthermore, care must be taken to ensure that the component from one container is not inadvertently transferred to the remaining bulk container where it might contaminate the other component or initiate a chemical reaction that adversely affects the characteristics of the other component.
In recent years, there has been increased interest in xe2x80x9csingle usexe2x80x9d containers for compositions made of two components that are initially kept apart from each other. Such containers typically avoid the need to measure out separate quantities of each component before mixing. These containers also help assure that the components, when mixed, are present in the desired ratio of the resulting composition. Additionally, if the components are mixed together within the container, the need for a mixing well, pad, container or other type of mixing structure is avoided.
Compositions made of two or more components that are initially kept separate from each other are also widely used in the field of medicine and dentistry, including orthodontia. For instance, many adhesives and cements used in dentistry are made of two components that are not mixed together until immediately prior to use. Examples of two-component dental compositions include RelyX ARC dental cement and F2000 primer/adhesive, both from 3M Company.
Single use containers for multiple component compositions are especially convenient for storing medical and dental compositions, because the container along with the applicator can be disposed of after use for a single patient. In this manner, the risk of transferring an infectious disease from one patient to another is substantially reduced. Oftentimes, only a relatively small quantity of the composition is needed at any one time, and the smaller xe2x80x9csingle dosexe2x80x9d or xe2x80x9csingle usexe2x80x9d containers help ensure that a freshly-mixed batch of the composition is available when needed.
Examples of containers that are especially suitable for isolated storage of components for multiple component compositions are described, for example, in U.S. Pat. Nos. 5,735,437, and 5,743,736. However, there is a continuing need to improve the state of the art so that the costs of manufacturing the containers is reduced. Preferably, such a container would be easy to use and yet provide reliable assurance that the shelf life for the stored components is satisfactory.
The present invention is related to an improved container for compositions that are made of two or more components. The container is especially suitable for single-use applications, such as those found in the field of dentistry. The container may be used for mixing and dispensing of the components in addition to storage of the components, such that the need to transfer the components to a separate location for mixing is rendered unnecessary.
In more detail, the present invention is directed in one aspect to a container for a composition made of two or more components. The container includes an outer housing having a chamber and an inner housing having a compartment. The inner housing includes a frangible wall portion and a first opening spaced from the frangible wall portion. A cover extends across the first opening. A first component is received in the chamber, and a second component is received in the compartment. The inner housing is received in the outer housing. The first component contacts the second component when the frangible wall portion is ruptured.
The present invention is also directed in another aspect to a container for a composition made of two or more components. In this aspect, the container includes an outer housing having a chamber and a puncturing tool. The container also includes an inner housing slidably received in the chamber of the outer housing. The inner housing has a compartment with a frangible wall portion. A first component is received in the chamber and a second component is received in the compartment. The inner housing is slidable in the chamber from a first position where the frangible wall portion is spaced from the puncturing tool to a second position where the frangible wall portion is ruptured by the puncturing tool such that the first component and the second component come into contact with each other.
The container according to the invention is an advantage, in that the inner housing can be manufactured separately from the outer housing if desired. As a consequence, the manufacturing steps of installing the frangible wall portion, connecting the cover and adding the two components to the container is facilitated. Optionally, both the inner housing and the outer housing can be inexpensively made of a plastic material and the cover and/or the frangible wall portion can be made using a metallic foil or plastic film that is fixed in place by a heat seal. As a result, the costs of the container are relatively low.
These and other features of the invention are described in more detail in the paragraphs that follow and are illustrated in the accompanying drawings.